Transcript (-) (-) Exploitation competition

Community Ecology: Species Interactions
5 Basic types of species interactions
1XXXXXXXXXX
?
2
Competition is important...just not as
important as predation (sometimes)
Competition ...common use of a limited resource
limited
What can be limiting....?
Food
Habitat
Nutrients
Between and within species??
Intraspecific competition
Interspecific competition
3 types of competition??
Interference competition
Exploitation competition
Apparent competition
Interference competition - occurs directly between
individuals via aggression etc. when the individuals
interfere with foraging, survival, reproduction of
others, or by directly preventing their physical
establishment in a portion of the habitat.
A
(-)
(-)
B
Exploitation competition - occurs indirectly through
a common, limiting resource, which acts as an
intermediate. Ex. depletes the amount of food or fill
up all the available space.
A
(-)
(-)
- + +
R
B
-
Apparent competition - occurs indirectly between
two species which are both preyed upon by the same
predator.
B
A
-
P
+
A
+
- -
P
B
+
http://video.google.com/videoplay?docid=6431936272692514162
food
density
Daphnia
Temperature
The Niche Concept
FUNDAMENTAL
REALIZED
A
B
habitat
pH
Salinity
2 dimension, but there are more....
The Niche Concept
• Sharing of resources alone not evidence of competition
• Niche overlap correlates with competition
4
3.5
Largemouth bass
3
2.5
Prey Weight
(Relative)
2
1.5
1
Green Sunfish
0.5
Bluegill
0
25
26
27
28
29
30
31
Temperature (Celsius)
32
33
34
Competition's role in ecology
and evolution
"species packing"
Population
Abundance
Population
Abundance
Resource partitioning
Resource
Gradient
Resource
Gradient
Lake Tanganyika
Lake Malawi
Cichlids exhibit remarkable evolutionary convergence. Similar ecomorphs have evolved repeatedly within different cichlid
assemblages. All of the cichlids in the left-hand column are from Lake Tanganyika. All of the cichlids in the right-hand
column are from Lake Malawi, and are more closely related to one another than to any species within Lake Tanganyika.
Note the similarities among color patterns and trophic morphologies.
Utilize resources along a gradient (See
Wooton)
– Food particle size
– Temperature
– Habitat
100
90
80
Fish Abundance
70
60
Sculpin
50
Dace
40
30
20
10
0
1
2
3
4
5
6
7
8
9
Station (1=downstream)
10
11
12
Examples: Classic Werner and Hall Experiments
Bluegill
Green Sunfish
Pumpkinseed
Examples: Ciscoes adaptive radiation (Lindsey 1981)
Individual Responses
•Behavior – feeding rate
•Physiology – growth rate
Population
Abundance
How do we see it or measure it?
•Morphological – body size
Population responses
•Abundance
•Distribution
Time
Modeling Competition
Lotka-volterra model
Competition coefficients
The equations
What the hell is an isocline, anyway?
– 4 graphs. See Molles
Population
Abundance
•
•
•
•
Time
Exotic Species
Exotic Species: A species not in its native range
Invasive/Nuisance Species: An exotic species that meets 3
criteria
Invasive fishes that affect the
ecology of native Wisconsin Fishes
Pelagic planktivores - Alewife, Rainbow smelt, white perch,
Benthic insectivores – round goby, common carp
Pelagic piscivores – Pacific salmon, brown trout
Pelagic/benthic parasite – Sea lamprey
Stream insectivores – brown trout, rainbow trout
Pelagic filter-feeders – silver carp, bighead carp
Non-fish Invasive Species that affect
the ecology of native Wisconsin Fishes
Pelagic Planktivore: Spiny Water Flea
Benthic Filter Feeder: Zebra Mussel, Quagga Mussel
Plant: Eurasian Water Milfoil
Exotic fishes utilize different habitats
And a variety of food sources
How do they get here?
People
Ships ballast water
Canals
Aquaculture
Ballast water
Alewife
White Perch
Round goby
Aquaculture
Silver carp
Bighead carp
Spiny Water Flea
Intentional
Stocking
Zebra Mussel
Pacific Salmon
Quagga Mussel
Brown trout
Rainbow trout
Canals
Common carp
Sea lamprey
Rainbow smelt
Rainbow smelt
4 aspects that make them so successful...?
High fecundity – lots of eggs / individual
Excellent competitors – better at gaining
resources then native species
Exploit a less well used resource
Lack of a natural predator
Questions Researchers Ask
• Impact
• Distribution Forecasting
• Prediction/Prevention
• Control
Detrimental to sport fisheries... round
gobies to smallmouth bass nests
http://www.glwi.uwm.edu/people/jjanssen/goby/index.html
Detrimental to ....life as we know it on all
lakes and rivers
http://www.youtube.com/watch?v=2ChwJiKKBdA